Propeller hub and blade mounting



Aug. 9, 1932. T. F. HAMILTON PROPELLER HUB AND BLADE MOUNTING Filed Nov. 8, 1928 2 Sheets-Sheet l R O T. N E V m ATTORN EYS Aug., 9, w51, T. F. l-lAwnLToNv Lgf/'0,361

PROPELLER HUB AND BLADE MOUNTING Filed. Nov. s. 1928 2 sheets-sheet 2 EM@ Q Jn/,M MM

INVENTOR BY My# MQ@ ATTORNEYS Patented Aug. 9, 1932 UNITED STATES PATENT OFFICE THOMAS F. HAMILTON,.OF MILWAUKEE WISCONSIN, ASSIGNOB, BY MESNE ASSIGN- MENTS, TOFHAMILTON STANDARD PROPELLER COMPANY, F WEST HOMESTEAD, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA rnorntnnn HUB AND BLADE MOUNTING.

Application led November 8, 1928. Serial No. 317,895.

My invention relates to propellers for air craft and more specifically to vproviding an improved means of mounting such blades so that though held with perfect security yet 5, they may be quickly and easily interchangea e. My invention has for its object to provide a novel form for the inner end of the propel- 1er blade which will not only be available for securing the blades to the hub but may also be used to balance the propeller blades.

My invention has for its further object to provide a mounting whereby the propeller y blades may be adjusted longitudinally of Il their axis. A

My means of accomplishing this object may be more readily understood byhaving'reference to the accompanying drawings, which are hereto annexed and are a part of this specification, in which .Fig. 1 is a view partly in elevation iand partly in section showing the propeller hub and blade end assembly;

Fig. 2 is a plan view of the deviceas shown in Fig. 1;

F Fig. 3- is a section taken on the line 3-*3 in ig. 1 Fig.,4 is a'modified form of my clamping and balancing mechanism; Fig. 5 is a different form of clamp; Fig. 6 is a detail of one of the bolts; and Fig. 7 is an enlarged detail of the threads on the hub. i

Similar reference numerals refer to similar partsthroughout the entire description. As shown in the drawings the propeller blades 1 are formed with hollow ends 2 which are provided with! internal threads 3. vSlots 4 are formed in the walls of the hollow ends E 2, `diametrically opposite to each 'other as clearly seen in Fig.l 3. Bosses 5are formed on' the exterior of the walls of the hollow ends 2 ,adjacent the slots 4 through which bolts 6 are passed. These bolts are preferably formed as shown in' Fig. 7 with extensions so that additional nuts 7 may be mounted thereon and may be used for balancing purposes. The hub 8 is constructed of a single forging which is provided with a central bore '9 whichis preferably tapered and fitted to the the bosses 5 I employ a split ring 20, which outer end 10 of the engine crank shaft being secured thereon 4in any of the standard wa s by which propeller hubs are mounted. Xs illustrated, a nut 11 serves to draw the tapered bore 9 tightly on to the end 10 of the shaft. A key 12 is also inserted in a key way or slot as is usual in such construction.

Two. arms -13 (or more if desired) extend from the hub 8. In practice I have found it desirable to make the arms 13 hollow as illustrated, thus attaining lightness without sacrificing needed strength. They are provided with external threads 14 which are fitted to and coincide with the internal threads 3 cut on the hollow ends 2 of the propeller blades 1. The surface `15, of the arms 13, adjacent the shaft mounting, is smooth, as is also the end 16 of the arm 13, these smooth surfaces fitting to similar surfaces formedfupon the inside of the hollow ends 2 of the propeller blades l.

In mounting the blades 1, they are screwed on t0 the arms 13 and adjusted until they reach the desired longitudinal and angular positions, when the nuts 17 are tightened on the bolts 6, and since the threads are cut as shown in Fig. 7 it will be apparent'thatthey provide uniform ta ered surfaces so that the ends 2 will be' rawn down and clamp the ends 2 of theJ blade 1 tightly upon the arms 13 of the hub 8. 'i

It may in some cases be deemed desirable to form more than one pa'ir of bosses on the blade ends, and to extend the slots 4 as shown in Fig. 4, although I have found in practice that a singlegclamp at the inner end of the blade holds it rigidly and satisfactorily in use.

As shown in Fig. 5, instead of providing is secured in place by a dowel 21. 'In the split ring the bolts used are similar to those employed in my preferred construction shown in Fig. 1, which is obviously very much cheaper as it does away with one additional part. When this type of clamping meansvis employed, if a proper fit is made between the propeller butt and the hub, it has been found in practice that it is not necessary to provide the slots 4 nor even to split 3 the end .of the propeller, as the metal .of which the blades are` cast or formed is suciently ductile to be compressed by the pressure exerted through 'the' bolts 6 upon the split ring 20 and, inv turn, upon the inn-er end of the propeller blade.

,Although I have described a specific form of construction, itis not to be understood that I am limited thereby, as the showing is merely to disclose a preferred form, and- 'many changes may be made 1n the detalls without departing from the scope of my in- Vention, and l therefore 'do not desire to be limited except as such limitations may appear in the hereinafter contained claims.

Having described my invention, what l regard as new, and desire to secure by lIettejrs Patent of the United States, is:

l. An aeronautical propeller blade mounting comprising a hub adapted to be mounted on an engine shaft., a plurality of radial integral arms extending from the hub, external threads on said arms, propeller blades having hollow internally threaded ends adapted to engage the threads on 'said arms, the hollow blade ends having diametrically dis-A posed slotspbosses on the blade ends on each side of each of said slots', and bolts in said bosses to clamp the blade ends on the huh arms.

2. An aeronautical propeller "blade mount- A ing comprising` a hub adapted to he mounted on an engine shaft7 a plurality of radial integral arms extending Jfrom the hub, external threads on said arms, propeller blades having hollow internally threaded ends adapted to engage the projections on said arms, the blade ends having a pair of diametrically disposed slot-sand means to clamp the slotted blade ends on the hub arms. l

3. An aeronautical propeller having'ductile blades with hollow ends and a hub with radial arms, wherein the hollow ends of the blades are screwed directly onto the arms of the hub and clamped to said arms by tension bolts acting to contract the hllow blade ends on said arms, said bolts being; provided with extra threads on their ends, andextra nuts mounted on said threads for balsnicing,n the bladess ll. An aeronautical propeller having ductile blades witlrhollow ends and a hub with radial arms,wherein thevhollow ends of the blades are screwed directly onto the arms of the hub and rmly clamped'to said arms by split ring' clamps placed around the hollow blade ends, the ends or" the said clamps being connected by tension bolts, said bolts having extra screw threads on their ends, 'and extra nuts mounted on said holts for balancing 

